Temporal patterns of phytoplankton phenology across high latitude lakes unveiled by long-term time series of satellite data

Monitoring temporal changes in phytoplankton dynamics in high latitude lakes is particularly timely for understanding the impacts of warming on aquatic ecosystems. In this study, we analyzed 33-years of high resolution (30 m) Landsat (LT) data for reconstructing seasonal patterns of chlorophyll a (chl a) concentration in four lakes across Finland, between 60°N and 64°N. Chl a models based on LT spectral bands were calibrated using 17-years (2000–2016) of field measurements collected across the four lakes. These models were then applied for estimating chl a using the entire LT-5 and 7 archives. Approximately 630 images, from 1984 to 2017, were analyzed for each lake. The chl a seasonal patterns were characterized using phenology metrics, and the time-series of LT-based chl a estimates were used for identifying temporal shifts in the seasonal patterns of chl a concentration. Our results showed an increase in the length of phytoplankton growth season in three of the lakes. The highest increase was observed in Lake Köyliönjärvi, where the length of growth season has increased by 28 days from the baseline period of 1984–1994 to 2007–2017. The increase in the length of season was mainly attributed to an earlier start of phytoplankton blooms. We further analyzed surface temperature (Ts) and precipitation data to verify if climatic factors could explain the shifts in the seasonal patterns of chl a. We found no direct relationship between Ts and chl a seasonal patterns. Similarly, the phenological metrics of Ts, in particular length of season, did not show significant temporal trends. On the other hand, we identify potential links between changes in precipitation patterns and the increase in the phytoplankton season length. We verified a significant increase in the rainfall contribution to the total precipitation during the autumn and winter, accompanied by a decline in snowfall volumes. This could indicate an increasing runoff volume during the beginning of spring, contributing to an earlier onset of the phytoplankton blooms, although further assessments are needed to analyze historical streamflow values and nearby land cover data. Likewise, additional studies are needed to better understand why chl a patterns in some lakes seem to be more resilient than in others.peerReviewe

Polycomb Repressive Complex 2 Regulates Genes Necessary for Intestinal Microfold Cell (M Cell) Development

BACKGROUND & AIMS: Microfold cells (M cells) are immunosurveillance epithelial cells located in the Peyer's patches (PPs) in the intestine and are responsible for monitoring and transcytosis of antigens, microorganisms, and pathogens. Mature M cells use the receptor glycoprotein 2 (GP2) to aid in transcytosis. Recent studies have shown transcription factors, Spi-B and SRY-Box Transcription Factor 8 (Sox8). are necessary for M-cell differentiation, but not sufficient. An exhaustive set of factors sufficient for differentiation and development of a mature GP2+ M cell remains elusive. Our aim was to understand the role of polycomb repressive complex 2 (PRC2) as an epigenetic regulator of M-cell development. Estrogen-related-receptor gamma (Esrrg), identified as a PRC2-regulated gene, was studied in depth, in addition to its relationship with Spi-B and Sox8. METHODS: Comparative chromatin immunoprecipitation and global run-on sequencing analysis of mouse intestinal organoids were performed in stem condition, enterocyte conditions, and receptor activator of nuclear factor kappa B ligand-induced M-cell condition. Esrrg, which was identified as one of the PRC2-regulated transcription factors, was studied in wild-type mice and knocked out in intestinal organoids using guide RNA's. Sox8 null mice were used to study Esrrg and its relation to Sox8. RESULTS: chromatin immunoprecipitation and global run-on sequencing analysis showed 12 novel PRC2 regulated transcription factors, PRC2-regulated Esrrg is a novel M-cell-specific transcription factor acting on a receptor activator of nuclear factor kappa B ligand-receptor activator of nuclear factor kappa B-induced nuclear factor-kappa B pathway, upstream of Sox8, and necessary but not sufficient for a mature M-cell marker of Gp2 expression. CONCLUSIONS: PRC2 regulates a significant set of genes in M cells including Esrrg, which is critical for M-cell development and differentiation. Loss of Esrrg led to an immature M-cell phenotype lacking in Sox8 and Gp2 expression. Transcript profiling: the data have been deposited in the NCBI Gene Expression Omnibus database (GSE157629).Peer reviewe

Editorial : Solving Complex Ocean Challenges Through Interdisciplinary Research: Advances from Early Career Marine Scientists

Non peer reviewe

Dynamic release of neuronal extracellular vesicles containing miR-21a-5p is induced by hypoxia

© 2022 The Authors. Journal of Extracellular Vesicles published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Hypoxia induces changes in the secretion of extracellular vesicles (EVs) in several non-neuronal cells and pathological conditions. EVs are packed with biomolecules, such as microRNA(miR)-21-5p, which respond to hypoxia. However, the true EV association of miR-21-5p, and its functional or biomarker relevance, are inadequately characterised. Neurons are extremely sensitive cells, and it is not known whether the secretion of neuronal EVs and miR-21-5p are altered upon hypoxia. Here, we characterised the temporal EV secretion profile and cell viability of neurons under hypoxia. Hypoxia induced a rapid increase of miR-21a-5p secretion in the EVs, which preceded the elevation of hypoxia-induced tissue or cellular miR-21a-5p. Prolonged hypoxia induced cell death and the release of morphologically distinct EVs. The EVs protected miR-21a-5p from enzymatic degradation but a remarkable fraction of miR-21a-5p remained fragile and non-EV associated. The increase in miR-21a-5p secretion may have biomarker potential, as high blood levels of miR-21-5p in stroke patients were associated with significant disability at hospital discharge. Our data provides an understanding of the dynamic regulation of EV secretion from neurons under hypoxia and provides a candidate for the prediction of recovery from ischemic stroke.This work was supported by the University of Eastern Finland, Emil Aaltonen Foundation, Paavo Nurmi Foundation, Saastamoinen Foundation, Instrumentarium Science Foundation and Business Finland (Grant number 4399/31/2019). Work with clinical samples was supported by the European Regional Development Fund - Project INBIO (No. CZ.02.1.01/0.0/0.0/16_026/0008451). Work with EVQuant was supported by the IMMPROVE Alpe d'HuZes grant of the Dutch Cancer Society (EMCR2015-8022) and the Daniel den Hoed Foundation grant for Erasmus MC Cancer Treatment Screening Facility. L.R. is supported by a predoctoral fellowship grant (IFI17/00012) and J.M. is the principal investigator of the grant PI18/804 ‘MULTI-BIO-TARGETS: a new strategy for stroke management combining outcome biomarkers and neuroprotection’, both from the Instituto de Salud Carlos III.Peer reviewe

The Quilt of Sustainable Ocean Governance : Patterns for Practitioners

In recent decades, scientists and practitioners have increasingly focused on identifying and codifying the best ways to manage activities in marine systems, leading to the development and implementation of concepts such as the social-ecological systems approach, ecosystem-based management, integrated management, marine spatial planning, participatory co-management, and the precautionary approach. To date, these concepts appear as separate entities: they have parallel literature streams; have been applied most often individually in attempts to improve governance and management; and in many ways, seem to be competing for attention. This patchwork of approaches may be hindering effective ocean governance. We propose that desirable features from these frameworks could be woven together to form the basis of more effective and equitable ocean governance arrangements across contexts, sectors, and scales. This article synthesizes the efforts of an IMBeR (Integrated Marine Biosphere Research Project) conference session and working group, that brought together experts in these diverse concepts with the objective of producing a synthesis of how they could be more effectively integrated for improved ocean sustainability outcomes. We reviewed and compared the concepts in terms of (a) the need to achieve a comprehensive suite of sustainability objectives, (b) similarities and differences in their scope, and (c) their place in practical management, policy and regulation. Achieving greater cross-sectoral integration, or a more holistic perspective on management for sustainability is at the core of each concept. All deal with aspects of governance and most, with improved participation in governance. The major differences in the origin and historical application of each concept are reflected in the degree of implicit or explicit focus given to different objectives of sustainability. Overall, the concepts are especially strong for ecological and institutional or governance considerations, moderately strong for economic aspects, and weakest for the social-cultural pillar of full spectrum sustainability. There is no panacea, and no emergent hierarchy among concepts. Some concepts fit better with top-down legislation-based efforts, others with more bottom-up stakeholder driven efforts. The selection of the core concepts for a situation will depend in a large part on which concepts are specified, or demand focus, in the legal and policy context of the situation (or area) of interest. No matter how influential or dominant a single concept might be, pragmatically, different concepts will be used in different areas, and there may always be the need for a combination of concepts and objectives woven together to achieve a cohesive quilt of sustainability.Peer reviewe

Dynamic release of neuronal extracellular vesicles containing miR-21a-5p is induced by hypoxia

Hypoxia induces changes in the secretion of extracellular vesicles (EVs) in several non-neuronal cells and pathological conditions. EVs are packed with biomolecules, such as microRNA(miR)-21-5p, which respond to hypoxia. However, the true EV association of miR-21-5p, and its functional or biomarker relevance, are inadequately characterised. Neurons are extremely sensitive cells, and it is not known whether the secretion of neuronal EVs and miR-21-5p are altered upon hypoxia. Here, we characterised the temporal EV secretion profile and cell viability of neurons under hypoxia. Hypoxia induced a rapid increase of miR-21a-5p secretion in the EVs, which preceded the elevation of hypoxia-induced tissue or cellular miR-21a-5p. Prolonged hypoxia induced cell death and the release of morphologically distinct EVs. The EVs protected miR-21a-5p from enzymatic degradation but a remarkable fraction of miR-21a-5p remained fragile and non-EV associated. The increase in miR-21a-5p secretion may have biomarker potential, as high blood levels of miR-21-5p in stroke patients were associated with significant disability at hospital discharge. Our data provides an understanding of the dynamic regulation of EV secretion from neurons under hypoxia and provides a candidate for the prediction of recovery from ischemic stroke

Risk Categorization Using New American College of Cardiology/American Heart Association Guidelines for Cholesterol Management and Its Relation to Alirocumab Treatment Following Acute Coronary Syndromes

10.1161/CIRCULATIONAHA.119.042551CIRCULATION140191578-158

Effect of Alirocumab on Mortality After Acute Coronary Syndromes An Analysis of the ODYSSEY OUTCOMES Randomized Clinical Trial

10.1161/CIRCULATIONAHA.118.038840CIRCULATION1402103-11